Rear shocks 411 513 031 l

[vwrenault]

I found those shocks at work not gas oil I will post in classified tomarow.

[raygreenwood]

Bear in mind they are REALLY old. Not good for shocks and hydraulics. Ray

[vwrenault]

I agree Ray so I will keep them for my car. I have 6 sets a lifetime of rear shocks .I want to make the oil full tube 021 115 655 i have New old stock one .can you help?

[raygreenwood]

With normal oil filled shocks. ...how they last when old.....will be mainly dependent upon how they are made.

Most shocks. ...unlike something like a brake master cylinder.....use metal piston rings. So the shock function will not break down with age. The risk is the top piston rod seal. Because these are usually spring backed rod wiper seals. As long as the seal has not deteriorated or shunk.....you may get very good life from them. Or they may run for a little while and then start leaking a lot.

The shocks that are much worse are the gas assisted or mixed oil and gas. With age the gas leakscand permeates both chambers and causes foam and incorrect valving.

So you want to reproduce the oil dip stick tube?

The difficult part is not making the three piece mold that is required. That can be made from plaster, epoxy etc.

The problem is getting acceptable materials to cast it from. The problems with a part like the oil dipstick tube.....is that it must be made from a rubber that is oil proof......not just grease proof.....but oil proof. Lots of contaminants and acidity to motor oil. And it must have relatively high temperature capabilities.

The rubber materials that fit these descriptions......are Viton, EPDM and in some cases EPR. These materials do not lend themselves readily to simple gravity or vacuum casting. They generally come as a liquid resin that is heat vulcanized or cured in a heated mold enough to be solid enough to release from the mold. Then they have to be baked or heat treated to complete the cure.

If this were a rubber part like the gasket around the door pillar switch....which rarely comes in contact with oil or grease and rarely more than 125°F.....it would be easy to make of something like silicone or urethane. Both of which can be cast as a catalyzed resin. Silicone except for certain gear oil resistant automotive RTV's......which are agressive and need to be vacuum and pressure cast......are generally not oil resistant enough to work for a part like this.

Urethane has oil resistance....but very poor heat resistance and life span.

I have been looking at some liquid EPDM coatings that are actually roofing materials. They dry by themselves and with a little heat. I have been thinking they may work for some parts like these. I have no idea if they have the same oil resistance as injection molded EPDM parts. Ray

[vwrenault]

Thanks Ray so I'm going to sell it . I'm using a 914 motor.